A pigment map is specified by...
Where NUM_1, NUM_2, ... are float values between 0.0 and 1.0 inclusive. A PIGMENT_BODY is anything that would normally appear inside a pigment statement but the pigment keyword and {} braces are not needed. Note that the [] brackets are part of the actual statement. They are not notational symbols denoting optional parts. The brackets surround each entry in the map. There may be from 2 to 256 entries in the map.
For example
When the gradient x function returns values from 0.0 to 0.3 the scaled wood pigment is used. From 0.3 to 0.6 the pigment identifier Jade is used. From 0.6 up to 0.9 a blend of Jade and a turbulent marble is used. From 0.9 on up only the turbulent marble is used.
Pigment maps may be nested to any level of complexity you desire. The pigments in a map may have color maps or pigment maps or any type of pigment you want. Any entry of a pigment map may be a solid color however if all entries are solid colors you should use a color map which will render slightly faster.
Entire pigments may also be used with the block patterns such as checker, hexagon and brick. For example...
Note that in the case of block patterns the pigment wrapping is required around the pigment information.
A pigment map is also used with the average pigment type. See "Average" for details.
You may not use pigment_map or individual pigments with an image_map. See section "Texture Maps" for an alternative way to do this.
Where FILE_TYPE is one of the following keywords gif, tga, iff, ppm, pgm, png or sys. This is followed by the name of the file in quotes. Several optional modifiers may follow the file specification. The modifiers are described below. Note that earlier versions of POV-Ray allowed some modifiers before the FILE_TYPE but that syntax is being phased out in favor of the syntax described here.
Filenames specified in the image_map statements will be searched for in the home (current) directory first and, if not found, will then be searched for in directories specified by any -L (library path) options active. This would facilitate keeping all your image maps files in a separate subdirectory and giving an -L option on the command line to where your library of image maps are.
By default, the image is mapped onto the x-y-plane. The image is projected onto the object as though there were a slide projector somewhere in the -z-direction. The image exactly fills the square area from (x,y) coordinates (0,0) to (1,1) regardless of the image's original size in pixels. If you would like to change this default you may translate, rotate or scale the pigment or texture to map it onto the object's surface as desired.
In section "Checker" the checker pigment pattern is explained. The checks are described as solid cubes of colored clay from which objects are carved. With image maps you should imagine that each pixel is a long, thin, square, colored rod that extends parallel to the z-axis. The image is made from rows and columns of these rods bundled together and the object is then carved from the bundle.
If you would like to change this default orientation you may translate, rotate or scale the pigment or texture to map it onto the object's surface as desired.
A map_type 0 gives the default planar mapping already described.
A map_type 1 gives a spherical mapping. It assumes that the object is a sphere of any size sitting at the origin. The y-axis is the north/south pole of the spherical mapping. The top and bottom edges of the image just touch the pole regardless of any scaling. The left edge of the image begins at the positive x-axis and wraps the image around the sphere from west to east in a -y-rotation. The image covers the sphere exactly once. The once keyword has no meaning for this mapping type.
With map_type 2 you get a cylindrical mapping. It assumes that a cylinder of any diameter lies along the y-axis. The image wraps around the cylinder just like the spherical map but the image remains one unit tall from y=0 to y=1. This band of color is repeated at all heights unless the once keyword is applied.
Finally map_type 5 is a torus or donut shaped mapping. It assumes that a torus of major radius one sits at the origin in the x-z-plane. The image is wrapped around similar to spherical or cylindrical maps. However the top and bottom edges of the map wrap over and under the torus where they meet each other on the inner rim.
Types 3 and 4 are still under development.
Note that the map_type option may also be applied to bump_map and material_map statements.
You can give the entire image a filter or transmit value using filter all VALUE or transmit all VALUE. For example:
Note that early versions of POV-Ray used the keyword alpha to specify filtered transparency however that word is often used to describe non-filtered transparency. For this reason alpha is no longer used.
See section "Specifying Colors" for details on the differences between filtered and non-filtered transparency.
PNG allows you to store a different transparency for each color index in the PNG file, if desired. If your paint programs support this feature of PNG you can do the transparency editing within your paint program rather than specifying transmit values for each color in the POV file. Since PNG and TGA image formats can also store full alpha channel (transparency) information you can generate image maps that have transparency which isn't dependent on the color of a pixel but rather its location in the image.
Although POV uses transmit 0.0 to specify no transparency and 1.0 to specify full transparency, the alpha data ranges from 0 to 255 in the opposite direction. Alpha data 0 means the same as transmit 1.0 and alpha data 255 produces transmit 0.0.
By adding a quick_color to a pigment you tell POV-Ray what solid color to use for quick renders instead of a patterned pigment. For example:
This tells POV-Ray to use solid Neon_Pink for test runs at quality +Q5 or lower but to use the turbulent gradient pattern for rendering at +Q6 and higher.
Note that solid color pigments such as
automatically set the quick_color to that value. You may override this if you want. Suppose you have 10 spheres on the screen and all are yellow. If you want to identify them individually you could give each a different quick_color like this:
and so on. At +Q6 or higher they will all be yellow but at +Q5 or lower each would be different colors so you could identify them.
Suppose you wanted a very bumpy surface on the object. It would be very difficult to mathematically model lots of bumps. We can however simulate the way bumps look by altering the way light reflects off of the surface. Reflection calculations depend on a vector called a surface normal vector. This is a vector which points away from the surface and is perpendicular to it. By artificially modifying (or perturbing) this normal vector you can simulate bumps.
The normal statement is the part of a texture which defines the pattern of normal perturbations to be applied to an object. Like the pigment statement, you can omit the surrounding texture block to save typing. Do not forget however that there is a texture implied. For example...
Note that attaching a normal pattern does not really modify the surface. It only affects the way light reflects or refracts at the surface so that it looks bumpy.
The most complete form for defining a normal is as follows:
Each of the items in a normal are optional but if they are present they should be in the order shown above to insure that the results are as expected. Any items after the NORMAL_IDENTIFIER modify or override settings given in the identifier. If no identifier is specified then the items modify the normal values in the current default texture. The PATTERN_TYPE may optionally be followed by a float value that controls the apparent depth of the bumps. Typical values range from 0.0 to 1.0 but any value may be used. Negative values invert the pattern. The default value if none is specified is 0.5.
Valid NORMAL_MODIFIERS are slope_map, normal_map, bump_map and bump_size statements as well as any of the generic PATTERN_MODIFIERS such as translate, rotate, scale, turbulence, wave shape and warp statements. Such modifiers apply only to the normal and not to other parts of the texture. Modifiers should be specified last.
There are three basic types of NORMAL_PATTERN_TYPEs. They are pattern normals, specialized normals and bump maps. They differ in the types of modifiers you may use with them. Originally POV-Ray had some patterns which were exclusively used for pigments while others were exclusively used for normals. Since POV-Ray 3.0 you can use any pattern for either pigments or normals. For example it is now valid to use ripples as a pigment or wood as a normal type. The patterns bumps, dents, ripples, waves, wrinkles and bump_map were once exclusively normal patterns which could not be used as pigments. Because these six types use specialized normal modification calculations they cannot have slope_map, normal_map or wave shape modifiers. All other normal pattern types may use them.
This gives a ramp wave pattern that looks like small linear ramps that climb from the points at x=0 to x=1 and then abruptly drops to 0 again to repeat the ramp from x=1 to x=2. A slope map turns this simple linear ramp into almost any wave shape you want. The syntax is as follows...
Note that the [] brackets are part of the actual statement. They are not notational symbols denoting optional parts. The brackets surround each entry in the slope map. There may be from 2 to 256 entries in the map.
The NUM_1, NUM_2, ... are float values between 0.0 and 1.0 inclusive. POINT_SLOPE_1, POINT_SLOPE_2, ... are 2 component vectors such as <0,1> where the first value represents the apparent height of the wave and the second value represents the slope of the wave at that point. The height should range between 0.0 and 1.0 but any value could be used.
The slope value is the change in height per unit of distance. For example a slope of zero means flat, a slope of 1.0 means slope upwards at a 45 degree angle and a slope of -1 means slope down at 45 degrees. Theoretically a slope straight up would have infinite slope. In practice, slope values should be kept in the range -3.0 to +3.0. Keep in mind that this is only the visually apparent slope. A normal does not actually change the surface.
For example here is how to make the ramp slope up for the first half and back down on the second half creating a triangle wave with a sharp peak in the center.
The pattern function is evaluated and the result is a value from 0.0 to 1.0. The first entry says that at x=0 the apparent height is 0 and the slope is 1. At x=0.5 we are at height 1 and slope is still up at 1. The third entry also specifies that at x=0.5 (actually at some tiny fraction above 0.5) we have height 1 but slope -1 which is downwards. Finally at x=1 we are at height 0 again and still sloping down with slope -1.
Although this example connects the points using straight lines the shape is actually a cubic spline. This example creates a smooth sine wave.
This example starts at height 0.5 sloping up at slope 1. At a fourth of the way through we are at the top of the curve at height 1 with slope 0 which is flat. The space between these two is a gentle curve because the start and end slopes are different. At half way we are at half height sloping down to bottom out at 3/4ths. By the end we are climbing at slope 1 again to complete the cycle. There are more examples in slopemap.pov in the sample scenes.
A slope_map may be used with any pattern except brick, checker, hexagon, bumps, dents, ripples, waves, wrinkles and bump_map.
You may declare and use slope map identifiers. For example:
Section 7.6.1.5
Image Maps
Section 7.6.1.5.1
Specifying an Image Map
Section 7.6.1.5.2
The map_type Option
Section 7.6.1.5.3
The Filter and Transmit Bitmap Modifiers
Section 7.6.1.5.4
Using the Alpha Channel
Section 7.6.1.6
Quick Color
Section 7.6.2
Normal
Section 7.6.2.1
Slope Maps
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